The present invention relates to a magnetic head and a method of manufacturing the magnetic head.
Recording density of magnetic disk drives and magnetic tape recorder have been made higher, so magnetic heads, which have narrow core width and capable of restricting record bleeding, are required.
Japanese Patent Gazette No. 11-7608 discloses a method of manufacturing a magnetic head having narrow core width, in which an upper magnetic pole is trimmed by a focussed ion beam (FIB). In the FIB trimming step, parts of a lower magnetic pole respectively located on the both sides of the upper magnetic pole are trimmed or grooved unit reaching prescribed depth, and width of the upper and lower magnetic poles are made equal so as to make recording density higher. Further, a distance between the upper magnetic pole and an upper face of the lower magnetic pole is made longer so as to prevent side erasure of magnetic flux and record bleeding as much as possible.
However, the above described conventional technology has following disadvantages.
FIG. 15 is a schematic view of the upper magnetic pole 10 and the lower magnetic pole 12 before the FIB trimming is executed. A gap layer 14 is made of alumina, SiO2, etc. FIG. 16 is a schematic view of the both after the FIB trimming is executed.
FIB is capable of trimming and forming the upper magnetic pole 10 into a narrow pole with high accuracy, but V-shaped grooves 16, which are inclined outward, are simultaneously formed at parts of the lower magnetic pole 12 located on the both sides of the upper magnetic pole 10. Therefore, edges 18 must be formed in the lower magnetic pole 12. Magnetic flux is apt to concentrate to the edges 18, so side erasure and record bleeding are apt to occur.
Further, if width of the grooves is made wider, by FIB, so as to make the distance between the edges 18 and the upper magnetic pole 10 longer, throughput must be sharply made lower.